Without limiting the scope of the present invention, its background will be described in relation to setting packers, as an example.
In the course of completing a subterranean well for hydrocarbon production, one or more packers are commonly installed in the well. The purpose of the packers is to support production tubing and other completion equipment and to provides a seal in the well annulus between the outside of the production tubing and the inside of the well casing to isolate fluid and pressure thereacross.
Certain production packers are set hydraulically by establishing a differential pressure across a setting piston. This may be accomplished, for example, by running a tubing plug on wireline, slick line, electric line, coiled tubing or another conveyance into the production tubing to a profile location. Fluid pressure within the production tubing may then be increased, thereby creating a pressure differential between the fluid within the production tubing and the fluid in the wellbore annulus. This pressure differential actuates a setting piston to axially compress and radially expand one or more seal elements of the production packer into sealing engagement with the casing. In addition, the force generated by the setting piston may be used radially expand one or more slip elements of the production packer into gripping engagement with the casing. Thereafter, the tubing plug is retrieved to the surface such that production operations may begin.
As operators increasingly pursue production in deeper water offshore wells, highly deviated wells and extended reach wells, for example, it has been found that production packers must be able to operate in increasingly higher operating pressures and under increasing axial forces. One limiting factor associated with production packers is the collapse strength of the packer mandrel. In the case of retrievable production packers having a single barrel slip, axial forces applied to the packer mandrel in addition to, for example, differential pressures in the well, translate to increased pressure on the packer mandrel proximate the seal elements. If the combined loading on the packer mandrel caused by the applied axial forces and the force generated by the differential pressures exceeds the collapse strength of the packer mandrel, a failure may occur. As such, it has been found, that some retrievable production packers having a single barrel slip are not suitable for certain high pressure operations.
Accordingly, a need has arisen for improved packer assembly for providing a seal between a tubular string and a wellbore surface. In addition, a need has arisen for such an improved packer assembly that is operable for use in higher pressure well operations.